The present invention relates to containers for growing plants, which containers have a lower water reservoir for delivering moisture to an upper soil-containing chamber in which the plants grow.
Because of the importance of delivering sufficient moisture to plants grown in a container, self-watering container systems (also known as planter systems) have been developed. These systems include a lower reservoir for storing water, an upper soil-containing chamber for growing plants, and various mechanisms for transferring moisture from the reservoir to the soil in the soil-containing chamber.
Known self-watering container systems typically do not have a sufficiently large reservoir proportionate to the volume of soil in the soil-containing chamber. As a consequence it is necessary to refill the reservoir more frequently than is desired, e.g., 2-3 times a day under certain circumstances. This reduces the benefit of the self-watering aspect of self-watering container systems. For example, U.S. Pat. No. 3,604,150 to Baumann describes a self-watering container system in which the volume of the lower reservoir is so small proportionate to the volume of soil that would typically be provided in the upper soil-containing chamber that use of such system would involve refilling the reservoir several times a day under certain growing conditions.
Another deficiency in known self-watering container systems is that the mechanism for transferring moisture to the soil-containing chamber does not transfer moisture in sufficient volumes or at sufficient rates to meet the needs of plants growing in the soil-containing chamber. This generally occurs because an insufficient portion of the soil in the soil-containing chamber is exposed to moisture in the reservoir. As a consequence, under certain growing conditions, even if the reservoir is full of water, insufficient moisture is delivered to the plants growing in the soil-containing chamber. For example, U.S. Pat. No. 3,271,900 to Mori describes a self-watering container having a lower water reservoir, a soil-containing chamber and two relatively small troughs extending downwardly from the chamber into the reservoir. The troughs have small slits through which moisture can pass from the reservoir into soil in the troughs. It is believed the size and number of troughs, and the size of the slits in the troughs, is insufficient to permit adequate moisture transfer via the troughs into the soil-containing chamber. In some cases, self-watering container systems suffer from both this problem and the problem described in the preceding paragraph.
It is also problematic if the soil-containing chamber in a self-watering container is exposed to too much moisture. In such case, the soil can become water-logged, thereby denying plants the carbon dioxide they need for survival.
Self-watering containers are well known. Unfortunately, because known self-watering containers typically suffer from one or more of the problems discussed above, their acceptance and use is not as widespread as possible.
Known self-watering containers typically include two parts, a lower container for holding water and a floor or planting tray for receiving soil and plants. Each of these parts is typically molded from plastic using a separate mold. Consequently, the total cost of manufacturing such containers typically requires amortization of two molds, and manufacturing throughput is limited by the need to form the two portions in separate manufacturing operations.
One aspect of the present invention is a self-watering planter. The planter comprises a reservoir for containing a first volume of water and a chamber for containing a second volume of planting medium positioned above the reservoir. The chamber includes a floor having a plurality of apertures extending therethrough. The planter includes a plurality of troughs, each having an open top end, a closed bottom end, an interior region for containing planting medium and at least one opening in the bottom end. The top end of each of the plurality of troughs is attached to the floor in alignment with one of the plurality of apertures so that its interior region is in communication with the chamber and each trough extends downwardly into the water reservoir. The interior regions in the plurality of troughs together contain a third volume of soil. The first volume is about 0.17 to 2 times the combination of the second volume and the third volume. The at least one openings in the plurality of troughs have a combined area that is 0.0005 to 0.030 inches2 per inch3 of the second volume, and the third volume is 2-11% of the second volume.
Another aspect of the present invention is a method of making a self-watering planter. The method includes the step of forming, in a single molding operation, a planter having a container with a bottom portion, a floor attached to the container, and an inner chamber positioned between the bottom portion and the floor. Next, the floor is separated from the container. Finally, the floor is positioned adjacent the bottom portion.
Still another aspect of the present invention is a self-watering planter that comprises a container having a bottom portion and a wall attached to the bottom portion so as to extend upwardly from the bottom portion. The planter includes a floor having a peripheral portion via which the floor is attached to the wall. The floor includes at least one trough extending downwardly toward the bottom portion, and the at least one trough has a bottom end. The floor is sized so that when it is detached at the peripheral portion from the wall and allowed to drop in the container toward the bottom portion so that the bottom end of the at least one trough is proximate the bottom portion, the peripheral portion engages the inner surface so as to limit planting medium positioned above the floor from passing past the floor and toward the bottom portion.